Current chassis control algorithms designed to enhance motor vehicle performance, e.g., reduce the likelihood of rollover, have usually employed feedback control. That is, a motor vehicle control system first detects undesirable motor vehicle performance, e.g., a danger of rollover, using sensors that measure a vehicle dynamic response, e.g., lateral acceleration, roll rate, yaw rate and/or wheel speeds. Upon detection of a rollover danger, one or more active automotive systems, e.g., a braking system, a suspension system and front and rear steering systems, have been activated to reduce lateral acceleration and correspondingly the likelihood of vehicle rollover. One drawback of a vehicle control system that implements feedback control is that the system response time must be relatively short for the system to restore vehicle stability before vehicle rollover occurs.
Unfortunately, in vehicle rollover events caused by a panic driver steering input, lateral acceleration, roll angle and roll rate of a vehicle can rapidly change, which places high demands on the control system and requires actuators (e.g., brakes) that have a relatively short response time. Additionally, a control system that implements feedback control also requires additional sensors, such as a roll rate sensor, and estimation algorithms (to determine rollover danger and the amount of control intervention that is necessary), which adds additional cost to the system.
What is needed is a roll angle control technique for a motor vehicle that is economical. It would also be desirable for the control technique to be capable of being implemented as a stand-alone control or in combination with other controls.